A crisis between three Latin American nations worsened Tuesday when Venezuela said it was closing its border with Colombia, even as frantic diplomatic talks to stave off war were about to begin.

Venezuelan Agriculture Minister Elia Jaua said "we have taken some measures, like closing the border," according to the Colombian television station Caracol.

The announcement aggravated a stand-off between Colombia and leftwing neighbors Venezuela and Ecuador that was triggered by a Colombian raid inside Ecuador to kill a senior FARC rebel commander.

An emergency session of the 34-member Organization of American States was to take place in Washington later Tuesday in a bid to quell the rising tensions.